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ST 100 MTB Cycling Helmet

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Sale price: LBP1,020,000.00

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Easy to use and adjustable, this mountain bike helmet has been designed for your rides up to 1.5 hours.

The comfortable ST 100 helmet protects your head from branches and impacts. It comes with nine ventilation holes that are larger than normal, to offer you better ventilation.

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Sale price: LBP1,020,000.00

Regular price:

Product Features

A photo of the ST 100 MTB Cycling Helmet in use

User comfort

Put on a well-fitting helmet with foam pads that you can forget you're wearing.


Adjust the helmet to your head using the adjustment dial.

Ease of use

Simplified adjustment, the straps are fixed under the ears.


Its 9 wide ventilation holes let air move through.

Impact protection

Complies with EN 1078.


Size M: 280 gSize L: 335 g

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Product Reviews

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2026 reviews

ST 100 MTB Cycling Helmet
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Cycle hat

It protects your bonnet

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Good quality.

Good quality and many offers.

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Good product

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Thank you for this helmet;)

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Fits just right, and light to wear.

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Great helmet. Good price

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Good price, attractive, fits well

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Bought with new bike

Fits as expected, good value for money

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Bike helmet

Nice price Good fit Head can get a bit chilly from the holes in the helmet but that can be rectified by wearing a thin beanie hat Feel much safer wearing one than not now :)

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Good helmet good price simples.

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Good product, Nice design

Overall this was a good product but it was too big for my wife. It is very difficult to size a person when not able to try on the product. No fault of Decathlaon.

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Decent quality helmet for the price

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Good cycling helmet

Good cycling helmet, good value and good fit

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Good value for a helmet that is for occasional use.

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Does what it needs to do

Bought one of these helmets at the start of the year and recently came off my bike on a downhill trail, quite concussed but the doctors are pretty sure this helmet saved my life. It may be a cheap helmet but it’s done it’s job.

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Additional Product informations



  • 100% EPS - Expanded Polystyrene


  • 100% Polycarbonate


  • 100% Polypropylene


9 vents.Chinstrap fastening: clipOccipital adjustment: dial.Comfort foam: fixed (available from after-sales)Visor: fixed, detachableOuter shell: bonded polycarbonate.Space requirements, size M: Length: 30 cm, width: 21 cm, height: 16 cm

How do you choose your mountain bike helmet size?

To find your helmet size, simply measure your head circumference (around the forehead).This mountain bike helmet is available in two sizes:M: 53 - 57 cmL: 57 - 62 cm

En 1078 certified

European standard setting out the requirements and test methods for helmets to be worn by users of rollerblades, skateboards, scooters and bicycles.The corresponding requirements and test methods cover the following aspects: construction, including field of vision; shock absorption properties; characteristics of the retention system, including the chinstrap and tightening devices; marking and information.

When should i replace my helmet?

We recommend replacing your helmet in 2 cases:1/ After a fallIn the event of a fall, the material of your helmet can deteriorate or even break. Sometimes, you won't even notice. That is why we recommend replacing it if you have the slightest doubt.2/ After 5 years of useThe foam of your helmet degrades over time. It can deteriorate due to impact, where it is stored, the climate, and its use. We recommend replacing your helmet at least every 5 years

How do you adjust the helmet?

Follow these 2 quick steps to adjust your helmet in 5 minutes:1/ Clip the 2 straps with the buckle: check that you can still slide 2 fingers between the strap and your chin.2/ Finally, adjust the tightness around your head.The helmet should be in contact with your head, without tipping forward, backward, or sideways, even when you're moving.

Product tests

Our team of product designers based at the B'Twin Village in Lille is continuously working to make cycling more comfortable for our users.Our obsession is to create products that meet the specific cycling needs of our users and eliminate things that get in the way of their rides.

A rating to compare products' environmental impact.

A product's environmental impact is calculated for its entire life cycle using various indicators.An overall rating (ABCDE) is given, allowing you to easily identify products with the best environmental performance by comparing similar products to each other (T-shirts, trousers, backpacks etc.).Decathlon openly displays the environmental ratings of its products.To find out more:

Returns conditions for personal protective equipment

Make sure that this product fits properly.If you do need to return it, you will need to make sure it still has its instructions, labels and, where applicable, original packaging. so that it can be reconditioned. Let's take care of our planet, together. conditions:

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